Chapter 81 - Acute and Recurrent Elbow Instability

Question 1

primary elbow STATIC restraints

Answer 1

Ulnohumeral articulation
Anterior bundle of the MCL
LCL complex (including the LUCL)

Question 2

secondary elbow STATIC restraints

Answer 2

capsule (most engaged in full extension)
radiocapitellar articulation (secondary valgus stabilizer)
common flexor and extensor origins

Question 3

Dynamic Constraints

Answer 3

mm that cross the elbow joint - apply compressive force
- anconeus
- triceps
- brachialis

coronoid blocks rotational instability and posterior subluxation of the ulna

Question 4

mechanism of injury for posterolateral dislocations

Answer 4

axial load, external rotation of the forearm (supination), and valgus force (valgus posterolateral)

***LCL is ALWAYS disrupted in an elbow dislocation

Question 5

stages of soft tissue disruption in posterolateral elbow dislocation

Answer 5

1. LUCL disruption
2. anterior/posterior capsule
3. MCL
   - 3a: partial
   - 3b: complete
   - 3c: distal humerus stripped of soft tissue - severe instability

Question 6

if the LCL is disrupted and the MCL is intact, how should you splint the arm?

Answer 6

pronation - activates the common extensor origin adding stability to the lateral side of the elbow

Question 7

if the LCL and the MCL are disrupted, how should you splint the elbow?

Answer 7

neutral rotation

Question 8

steps to open repair a elbow dislocation

Answer 8

1. LCL first
2. reassess stability -> if unstable ->
3. MCL

Question 9

most common complication following elbow dislocation

Answer 9

stiffness by far

can get recurrent instability but less common

Question 10

varus malunion of a distal humeral fracture may lead to what elbow instability syndrome?

Answer 10

posterolateral rotatory instability

Question 11

varus malunion of a supracondylar humeral fracture can cause what elbow instability syndrome?

Answer 11

tardy posterolateral instability

Question 12

in PLRI where is the LUCL torn?

Answer 12

avulsed from the proximal humeral origin

Question 13

essential lesion in posteromedial varus instability

Answer 13

LUCL injury
coronoid fracture (usually anteromedial facet)

Question 14

open treatment of varus posteromedial instability consists of what?

Answer 14

LCL and LUCL reconstruction/repair
Coronoid ORIF